This invention relates to pressure testers connected directly to pipes to measure the pressure of fluid inside the pipes.
Sections of piping systems containing fluid under pressure may, from time to time, require replacement. Often, there may be no pressure gauge proximal to the section being replaced. Moreover, in complex piping systems or where portions of the system are either inaccessible or not easily traceable, it may be difficult if not impossible to determine whether the section of the piping system to be replaced has been isolated from the Test of the system or to be certain that the pressure gauge being relied upon is not isolated from the section to be replaced. For example, in a sprinkler system installed in a building, a sprinkler head may need to be replaced that physically resides in an office or other space containing electrical equipment such as computers, in addition to documents and books. Thus, it is advantageous when removing a section of piping to know the pressure in the pipe and to be able to drain or otherwise remove the fluid in the pipe substantially without leakage.
The Andersson U.S. Pat. No. 5,971,001 discloses a fitting assembly clamped to the outside of a fluid filled conduit along with a threaded bushing having an axial bore for guiding a drill to drill a hole in the side of the conduit. After the hole has been drilled, the drill is removed and a sensing unit is connected to the bushing for sensing a characteristic of the fluid in the conduit. The Tuttle et al. U.S. Pat. No. 5,396,814 discloses an arrangement for hot tapping a pipe by mounting an assembly having a drill guide extending at an angle to the pipe and drilling a hole in the pipe and then replacing the drill with a cleaning assembly to remove metal shavings. In this case, the fluid in the pipe may be under pressure and the drill is withdrawn through a valve which can then be closed to prevent leakage of the fluid. A sensor carrier retainer attached to the valve may be opened to permit insertion of a sensor which is then detached from the carrier. The Nelson et al. U.S. Pat. No. 4,788,871 shows a probe having a hollow tube with a piercing end which is forced through the plastic wall of a container and has a threaded external part which is secured to the plastic wall. The Wetzel U.S. Pat. No. 4,577,511 discloses an air line pressure tester having a sensing probe which is inserted between resilient caskets into the interior of a pipe to detect pressure in the pipe.
Accordingly, it is an object of the present invention to provide a direct connect pressure tester arrangement which overcomes disadvantages of the prior art.
Another object of the present invention is to provide a portable arrangement for testing the pressure of a fluid in a pipe to be removed that substantially minimizes unwanted leakage when determining the pressure in the pipe and when removing the pipe.
These and other objects of the invention are attained by providing a pressure tester arrangement for determining the pressure of a fluid inside a pipe that includes a saddle clamped to the outside of the pipe, a passage extending from the outside of the wall of the pipe and through the saddle for receiving a drill bit movable within the passage for drilling a hole in the pipe, and a branch line for receiving a pressure gauge for determining the pressure in the pipe to which the tester is connected.
In one aspect of the invention, the pressure tester arrangement includes a plug coupled to the end of the passage distal to the saddle. The plug includes an axial channel for receiving the drill bit. The plug further includes a groove in the axial channel for receiving an O-ring through which the shank of the drill bit is inserted. A collar is fixably coupled to the drill bit forming a drill bit assembly. The drill bit assembly is slidably moveable in the passage such that the collar is moveable between the saddle and the plug.
In another aspect of the invention, the pressure tester arrangement further includes a valve coupled between the crosspipe and the plug. The length between the collar and the end of the drill bit distal to the plug is less than the length between the valve and the plug such that the valve is closable when the drill bit assembly is retracted when the collar is adjacent to the plug.
In another aspect of the invention, the pressure tester arrangement includes a ball and the axial channel of the plug further includes a larger diameter portion proximal to the saddle, a smaller diameter portion distal to the saddle and a tapered section between the smaller and larger portions. The diameter of the ball is sufficient when seated against the tapered section to form a seal. A bushing is coupled between the saddle and the plug wherein the bushing includes a threaded channel for receiving the plug, a cavity extending from the threaded channel, and a drill guide subassembly inserted in the cavity. The diameter of the cavity is sufficiently large and the diameter of the ball is sufficiently small such that the ball when residing in the cavity is not in line with an opening in the drill guide subassembly for receiving the drill bit. The diameter of the opening in the drill guide subassembly is smaller than the diameter of the ball.
In an additional aspect of the invention, the pressure tester arrangement includes a valve coupled between the crosspipe and the plug. The crosspipe is coupled to the saddle for connecting the passage to the branch line to the pressure gauge and for connecting the passage to a drain line. The drain line includes a drain valve coupled to the crosspipe.
In another aspect of the invention, at least one drill guide is inserted in the passage and a curved center section is coupled between the pipe and the saddle forming a seal between the pipe and the saddle. The saddle contains one of the drill guides. In this embodiment, the curved center section is composed of a resilient material.
In an aspect of the invention, the saddle further includes a pair of forked ends for receiving a U-bolt. The pipe is clamped between the saddle and the U-bolt.
In an additional aspect of the invention, the pressure gauge is coupled to the branch line and the drill bit is inserted in the passage. A drill is coupled to the drill bit.
In a further aspect of the invention, a direct connect pressure tester arrangement is provided including a passage comprising a saddle clamped to a pipe capable of containing fluid under pressure, a drill guide with an opening extending perpendicular to the wall of the pipe, a resilient member between the saddle and the outer wall of the pipe forming a seal, a crosspipe attached to a bushing mounted in the saddle, a valve attached to the crosspipe in axial alignment with the bushing and a plug coupled to the valve. The plug includes a channel. A drill bit is received in the passage. A pressure gauge is mounted in a perpendicular passage of the crosspipe and a drain valve is attached to the crosspipe in axial alignment with the pressure gauge. The plug receives the drill bit in the channel, forming a seal between the plug and the drill bit.
After the pressure tester has been mounted on the pipe to be tested, the valve adjacent to the drill is turned to the open position and the drill bit is moved through the valve and the drill guide and operated to drill a hole in the pipe. The pressure gauge will then indicate the presence of any fluid under pressure in the pipe. The drill can then be withdrawn through the crosspipe and the open valve which can then be shut and the drain valve can be opened to drain to any fluid under pressure from the pipe being tested.